Proof of Elapsed Time (PoT)
Intel presented an alternative consensus protocol, called proof of elapsed time. It works like Proof of Work but is more efficient in terms of energy usage. No puzzle is to be solved, a trusted execution environment (TEE) is used to ensure that blocks get created in a randomized lottery fashion. It is based on a guaranteed wait time that is provided by the TEE. The drawback in this model is its need for specialized hardware and having to trust a third party Intel.
IMHO, any solution that requires trust in a centralized third party is absolutely inappropriate for a cryptocurrency. The whole purpose of cryptocurrency is to
eliminate the need for trusting centralized third parties. A cryptocurrency that depends on centralized trust is the worst of both worlds: it has both the necessary inefficiencies needed for a trustless system and the failure modes that arise from centralized trust.